This invention relates in general to safety seat belt buckles and, more particularly, to a design which provides an optimum combination of design features and parameters to provide a functional combination of high strength, small size, low weight, ease of use and versatility in use together with a reasonable cost to manufacture.
There are a large number of safety seat belt designs which have been used and are being used as well as a large number of designs that have been proposed and are known in the art. It is simple enough to design a buckle to readily meet any one of two given functional criteria as long as other functional criteria are sacrificed. However, as a practical matter there must be a trade-off between such characteristics as low weight and small size on the one hand and structural strength on the other hand. Ease and cost of manufacture is another feature which must be traded off against both weight and size as well as against strength. Other important functional features are ease of manipulation so that the passenger or driver can readily buckle and unbuckle when required. Furthermore, since the use of a seat belt requires some degree of minimum acceptance by the riding public, aesthetic features and simplicity in use as well as weight and size are factors to take into consideration in any given design in order to enhance the likelihood that as large a number of users as possible will in fact use the seat belt rather than try to defeat any system in which the seat belts are used.
Accordingly, the main purpose of this invention is in a seat belt buckle design that provides an optimum combination of parameters that include weight, strength, size, ease of use, reliability, and ease and cost of manufacture.
It is a further purpose of this invention to provide a basic seat belt buckle design which has versatility in that (a) it can be used for a seat belt buckle which either incorporates or omits an electrical switch for an interlock system and (b) it can be used either for a center seat buckle or an outboard seat buckle wherein these two buckles are designed to prevent improper hookup of an outboard seat buckle with a center seat clip and prevent improper hookup of a center seat buckle with an end seat clip. In effect, versatility is another parameter which is part of the optimum combination of parameters to which this invention is addressed.